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Tank:A11 T29
|Gallery= image:T29_001.jpg T29_001 image:T29_002.jpg T29_002 image:T29_003.jpg T29_003 image:T29_004.jpg T29_004 image:T29-a1.jpg T29, map Karelia |History= By the middle of 1944, combat reports from Europe describing the use of heavy tanks by the Germans stimulated new interest in the development of an equivalent American vehicle. The Pershing medium tank provided an answer to the early model of the German Pz.Kpfw. VI Tiger. However, although the latter was still in first-line service, it had first been encountered by U. S. Army during 1943. By 1944, the Germans were introducing even more heavily armed and armored vehicles(Pz.Kpfw. Tiger II). Although for morale purposes the M26 Pershing was temporarily redesignated as a heavy tank, it clearly did not provide an answer to the problem. On 14 September 1944, U. S. forces recommended development and manufacture of four prototypes of a new heavy tank. Two of these were designated as the heavy tank T29 and were to be armed with the 105mm gun T5E1. The remaining two were designated as the heavy tank T30 and were to be armed with the 155mm gun T7. Technical info thumb|200px|left|T29E2 Prototype-technical drawingsOn 1 March 1945, an order for 1200 T29 tanks was recommended by the U.S. Army. The new heavy tank was powered by the Ford GAC V-12, liquid- cooled engine developing 770 horsepower at 2800 rpm. The engine was coupled to the new cross-drive transmission developed by General Motors. The latter combined the functions of a transmission, steering gear, and brakes in a single unit. With the original cross drive model EX-120, the driver used an electric control system to operate the transmission under normal conditions. Two mechanical manual steering levers also were provided for emergency use. Lack of sensitivity and feel with the electric control resulted in its replacement by a mechanical system also using a single control lever, usually referred to as the "wobble stick". The manual steering levers were retained for emergency use. Separate controls were provided for the driver and assistant driver (bow-gunner).thumb|200px|right|T29E3 Prototype-technical drawings When delivered to the Army, the T29s were fitted with the CD-850-1 version of the cross-drive transmission. This unit incorporated two hydraulically-selected gear ranges driving through a single phase torque converter. Part of the power was transmitted through a mechanical path, bypassing the torque converter. This mechanically transmitted power, as well as that from the torque converter, was applied equally to both output shafts except when steering. At that time, all of the mechanical power was applied to one side to provide the speed difference required for steering. Braking for the vehicle was by means of built-in disc brakes actuated mechanically by foot pedals in the driver's compartment. A later version of the cross-drive was installed during the testing program. Designated as the CD-850-2, it replaced the single phase torque converter with a polyphase unit. This later model was more efficient at high speeds and acted as a fluid coupling after the point of 1:1 torque multiplication was reached. The great advantage of the cross-drive transmission was its simplicity of operation, which greatly eased the task of the driver. Pushing the wobble stick to the left or right steered the tank in that direction when the transmission was in first or second gear. The same action in neutral caused the vehicle to pivot in place with one track going forward and the other in reverse. Such action greatly increased the ability of the tank to extricate itself from difficult terrain where less agile vehicles would be stuck. Many components in common with the medium tank M26 Pershing were used in the new heavy tanks. The T80E3 tracks were the 23 inch T80E1 tracks of the Pershing fitted with five inch extended end-connecters, giving a total width of 28 inches. Power was transmitted to the tracks through sprockets at the rear of the vehicle. Eight road wheels per side increased the ground contact length to reduce the ground pressure of the tank which weighed over 70 tons, combat loaded. The hull was a welded assembly of armor castings and rolled plate similar to the M26. The same maximum thickness of four inches was retained on the upper front, but the angle was increased on the T29 to 54 degrees from the vertical. The driver and assistant driver (bow-gunner) were seated on the left and right sides of the front hull respectively. The latter operated the .30 caliber machine gun ball mounted in the front armor. Both the driver and assistant driver were provided with a single periscope in their hatch covers. Crew The large cast turret was installed on an 80 inch diameter ring well forward on the hull. The turret armor thickness varied from seven inches on the front to four inches on the rear. A crew of four manned the turret with the tank commander seated under a cupola in the center of the turret-bustle. The gunner was located in the right front of the turret and was provided with a direct-sight telescope in the gun mount and a periscopic sight in the turret roof. The two loaders worked in the rear of the turret ring, one on each side of the cannon. Two hatches, one on each side, were located in the turret roof in addition to the hatch in the commander's cupola. A circular pistol port was installed in the right side wall of the turret. The 105mm gun T5E1, installed in the combination gun mount T123, was a long-barreled weapon with a muzzle velocity of 3000 feet per second using the 39 pound armor piercing shot (AP) T32. During tests, a 24.6 pound hypervelocity armor piercing shot (HVAP) T29E3 achieved a muzzle velocity of 3700 feet per second. A 33.5 pound T30E1 high explosive shell (HE) was provided with a reduced muzzle velocity of 2500 feet per second. A total of 63 rounds of 105mm ammunition was stowed in the turret and hull. Two .50 caliber machine guns were mounted coaxially on the left side of the 105mm gun. Another .50 caliber machine gun was fitted on a pedestal mount in front of the left loader's hatch on the turret roof. Ventilation was provided by two 1500cfm blowers. One was mounted in the turret roof to the right rear of the commander's station, and the other was located in the front hull roof between the driver and the assistant driver. History An order for the T29 tank was approved on 12 April 1945, but the numbers were reduced to 1152. Also in April, four additional prototype T29s were authorized, but later, it was directed that one of these was to be armed with the 120mm gun T53 and redesignated as the heavy tank T34. This was only one of the many changes to the program with the approaching end of hostilities. After the end of the war in the Pacific, the production contract with the Pressed Steel Car Company, Inc. was terminated with one T29 completed and a second partially finished. All material was transferred to Detroit Arsenal for the completion of ten prototypes for postwar development studies authorized on 23 August, 1945. Later, the total of T29 prototypes was reduced to eight. Models thumb|200px|right|T29E2 PrototypeThe first T29 arrived at Aberdeen Proving Ground in October 1947. By this time, there was no longer any requirement for production of these heavy tanks and the test program was limited to evaluating the various power train components for application to new tank designs. Two additional T29s arrived at Aberdeen in April and May 1948 and they also were used in the endurance and engineering test programs. T29 number 1 was diverted to General Motors Corporation for the installation of a modified version of the Allison liquid-cooled V-12 aircraft engine. To accommodate the new power package consisting of the Allison V-1710-E32 engine and the CD-850-1 cross-drive transmission, the tank hull was lengthened by 1 31/32 inches. The new engine developed 870 gross horsepower at 2800 rpm and weighed about 1600 pounds dry. This vehicle, armed with the 105mm gun T5EI in mount T123, was designated as the heavy tank T29E1 in December 1945. T29 number 2 was fitted with what was designated as the heavy tank turret T5. This turret was equipped with the Massachusetts Institute of Technology combination hydraulic power turret traversing and elevating mechanism and computing sight. The tank was armed with the 105mm gun T5E2 in mount T123E2. OCM 32107, dated I April 1948, designated the T29 with the T5 turret as the heavy tank T29E2. At this point, a brief description of the guns and mounts is in order. The 105mm gun T5E1 was installed in mount T123, which used three recoil cylinders on top of the gun cradle. This design was modified to have two recoil cylinders on top of the cradle and one on the bottom. This new mount was the T123E1 and the cannon modified to fit it was the 105mm gun T5E2. Installation of the power traversing and elevating system in the T29E2 tank required further modification of the mount, and it received the new designation T123E2. Heavy tanks T29 numbers 3, 4, 5, 6, and 7 were all armed with the 105mm gun T5E2 in mount T123E1. Heavy lank T29 number 8 was armed with the 105mm gun T5EI in mount T123. This vehicle was modified to provide for the installation of the range finder T31E1 and telescopic T93E2 in mount TI36. Provision also was made to install panoramic telescopes T141, T144, and T145 to evaluate their use during indirect fire with the 105mm gun. The T141 and T144 telescopes were used in the gunner's periscopic sight mount, and a T156 mount for the T145 telescope was fitted into the turret roof. thumb|200px|left|T29E3 PrototypeAll this was part of a program to study the effectiveness of integrated fire control systems. The same program also utilized a modified version of the medium tank T25E1. When fitted with the new fire control system, T29 number 8 was redesignated as the heavy tank T29E3. The T31E1 range-finder was a stereoscopic instrument with a base length of nine feet. It was not connected to the other fire control system components and was operated by the tank commander, who manually relayed the range information using the control box just below the range finder. When the range and the desired lead were set into the control box, it was transmitted by flexible shafting to the telescope mount T136. Thus the gunner could give his undivided attention to tracking the target. Unfortunately, it did not work very well in practice. The tests at Aberdeen showed that backlash, as well as windup and binding of the flexible shafting, introduced serious errors into the system. However, the test program did show that the stereoscopic range-finder was particularly useful for spotting purposes and sensing bursts. It also emphasized the necessity for a range-finder, if first-round hits were to be obtained at ranges over 1000 yards. T-series prototypes The T29, T30, T32, and T34 series of tanks were used to evaluate numerous experimental components after World War II. Although too late for the war for which they were designed, they provided invaluable service in developing these components for later tanks. Much of the work which made the early AV-1790 engine and the CD-850 transmission a reliable power package utilized these tanks. Later, they were used in the development of other power train components such as the XT-1400 transmission, which was tested in the T30. American Heavy tank comparison Mk.VII M6 T28 T29 T30 T32 T34 M103A2 Crew 8 6 4 6 6 5 6 5 Length 10,43m 8,43m 11,12m 11,56m 10,9m 10,83m 11,77m 11,23m Width 3,66m 3,12m 4,54m 3,8m 3,8m 3,76m 3,8m 3,63m Height 3,12m 3,00m 2,86m 3,22m 3,22m 2,81m 3,22m 3,56m Weight 39,5t 57,4t 86,3t 64,25t 64,74t 54,5t 65,2t 58,1t Engine power Liberty 338hp G-200 960hp GAF 500hp GAC 770hp AV1790 810hp GAC 770hp AV1790 810hp AV1790 750hp Max. speed 8,8km/h 35km/h 12,8km/h 35km/h 35km/h 35km/h 35km/h 37km/h hull armour (angle) 12mm (28) 83mm (30) 305mm 102mm (54) 102mm (54) 127mm (54) 102mm (54) 127mm (60) side armour 12mm 70mm 152mm 76mm 76mm 76mm 76mm 51mm Turret armour (mantlet) 16mm 83mm (102mm) - 178mm (279mm) 178mm (279mm) 298mm (298mm) 178mm (279mm) 127mm (254mm) top armour 6-10mm 25mm 38mm 38mm 38mm 38mm 38mm 38mm bottom armour 6-8mm 25mm 25mm 25mm 25mm 25mm 25mm 38mm Gun 2x57mm Hotchkiss 75mm M7 37mm MB 105mm T5E1 105mm T5E2 155mm T7 90mm T15E2 120mm T53 120mm M58 Secondary armament 5x7,62mm Hotchkiss 2x12,7mm HB M2 2x7,62mm M1919A4 12,7mm HB M2 3x12,7mm HB M2 7.62mm M1919M4 2x12,7mm HB M2 7.62mm M1919M4 12,7mm HB M2 2x7.62mm M1919M4 3x12,7mm HB M2 7.62mm M1919M4 3x12,7mm HB M2 7.62mm M37 |HistoricalGallery= image:T29.jpg T29 Prototype image:T29e3_1947_source_picassa.jpg T29E3 Prototype 1947 image:T29e3_top_view.jpg T29E3 top view |Ref_references= |Ref_sources= Hunnicutt, R.P., 1988, Firepower: A History of the American Heavy Tank, Presidio Press, 222p, ISBN:9780891413042. |Ref_links= *[http://www.wwiivehicles.com/usa/tanks-heavy/t29-t30-t32.asp T29 Heavy Tank] Photos & history. * http://svsm.org/gallery/T29E3 - T29E3, Patton Museum, by Matthew Flegal * http://armor.kiev.ua/Tanks/Modern/Heavy/ }} Category:USA Tanks